Electrolytic process and cell



July 15 .1924. 1,501,756

J. c. DOWNS I ELECTROLYTIC PROCESS AND CELL Filed Aug. 18I 1922 I ll? ZINVENTOR Arm/mu Patented July 15, 1924.

UNITED STATES PATENT OFFICE.

um GLOYD DOWNS, OI NIAGARA FALLS, NEW YORK, ASSIGNOi T In menu. Q

HASSLAGBEB CHEMICAL COMPANY, 01' NEW YORK,

YORK.

N. Y., A CORPORATION O! m ELECTROLYTIC PROCESS AND CELL.

Application filed August 18, 1922. Serial 10. 582,582.

To all whom it may concern: I

Be it known that 1, JAMES CLoYD Downs, .a citizen of the United States,and resident of Niagara Falls, in the county of Niagara 6 and State ofNew York, have invented certain new and useful Electrolytic Processesand Cells, of which the following is a specification.

My invention relates to the process of pro- 1 ducing alkali metals andhalogens by electrolysis of fused halide baths, as for example, sodiumchloride. An object of the invention is to recover halogens containingpractically no gaseous impurities. Another 1 object of my invention isto recover metals,

as for example, sodium, with a small expenditure of labor. Anotherobject of my invention is to provide means for charging raw material, asfor example, sodium chloride, into the electrolytic cell without in anyway introducing impurities into the chlorine or the sodium and withoutcomplicating the recovery of either of the primary products. Manyprocesses and types of electrolytic cells are known to those who areskilled in the art of manufacturing alkali metals. It is likewise knownthat the recovery of gases such as pure chlorine from electrolytic cellsutilizing fused baths consisting largely of sodium chloride ispractically impossible with any of the types heretofore described inpatent or other literature. My cell not only produces sodium from fusedbaths as efficiently, and permits of its recovery as easily as any cellheretofore known, but it has the distinct and valuable advantage thatchlorine gas can be recovered almost 100% pure, at least as pure as isnormally obtained from cells producing caustic soda and chlorine fromaqueous solutions of sodium chloride.

One of the characteristics of cells electrolyzing aqueous solution isthat the gas produced is always moist and is not readily usable in manychemical processes until after being dried. One of the advantages of thecells using fused salt baths is that the gas is given off dry; thisadvantage however, is lost in all types of cells previously builtbecause of the fact that moist air om without the cell cannot beexcluded from the chamber that collects and delivers gas produced at theanode. In all such cells heretofore described it has been im ossible torecover as dry chlorine the gas t at is produced by the electrolysis ofsodium chloride. Consequently the di ute and humid condition 0 thechlorine in many cases makes it a liability rather than an asset.

Meeting this outstanding weakness of all previous cells I have inventeda new ty from which pure dry chlorine can be easil and continuouslyrecovered; furthermorql have provided means by which pure sodium can beeasily removed, and the additional new feature that raw material, whichis usually sodium chloride, is introduced into a chamber distinct fromthose in which chlorine and sodium collect. Hence moisture that may bepresent in the solid sodium chloride is driven away from the fused bathbefore it may react chemically with any of the contents of the other twochambers. I have therefore invented a new type of cell consistin ofthree chambers each efl'ectively separate from the other, and a bathhaving a lower electrolyzing portion and an upper reservoir portion.

My cell fdr the electrolysis of sodium chloride is illustrated by thedrawing which is a vertical cross-section. The most simple form of thecell is one that is square in horizontal cross-section and square orrectangular in vertical cross-section. A is the anode, B is an annularcathode, F is a collecting chamber and dome for collecting the chlorine,G is an annular sodium collector, L and M are metal diaphragms supportedby F. H is a riser pipe for collectin and conducting the sodlum awaythroug the ipe I to a vessel J. K is a pipe through w ich the purechlorine .is delivered after being collected in F. The shell C of thecell is made preferably of iron plates and is lined with resistantrefractory material such as fire brick. One of the three chambers isentirely outside of the chlorine collector and above the sodiumcollector. Into this the material to be electrolyzed is fed through ahole N in the cover, although the cell may be 0 rated without a cover.Another of the c ambers is entirely within the chlorine compartment Fand the depending annular diaphragm L, the third chamber is included byannular collector G and that region below G and outside the diaphragm Land inside the annular diaphragm M. The bath level is shown by thedotted line 0.

The anode is preferably of graphite or carbon and the Cathode of iron orcopper.

Suitable water cooled connections and heat insulators may be used andmust be properly pro orticned to the cellca acity.

e operation of this cel 1s slmple. The direct current liberates chlorineat the anode and sodium at the cathode. The chlorine rises to thesurface of the bath at F and passes out at K under its own'pressure. Thesodium likewise rises, is can ht under G and passes u wardly in H. Sincesodium has a somew at lower density than the fused bath a column ofsodium forms and eventually stands high enough in H. to overflow throughIinto J. Continuous production of sodium results in a practicallycontinuous overflow. The bath level is maintained constant byintroducing raw material which is usually sodium chloride through a feedhole N in the cover. There being a large surface exposure of the bathsodium chloride may be introduced directly into the bath where it ismelted by the heat of the latter. Any moisture that may be present inthe solid sodium chloride is expelled from the bath and having no we ofaccess to the chlorine and sodium chambers said moisture is ultimatelydriven to the outside air.

I do not wish to be limited to the production of sodium and, chlorine inmy cell, but specifically include all alkali metals, and all halogens.

Neither do I wish to be limited to cells having one solid continuousanode and. one solid continuous cathode, because composite electrodesmay under some conditions be used advantageously.

As a means of confining the two primary products out of contact with thefeeding chamber as well as out of contact with each other, I do not wishto be limited to the use of three compartments. The simplest form ofcell is one with substantially concentric electrodes and with threesubstantially concentric compartments; however, more complex cells maybe designed and constructed in which case more than three compartmentsmight be advanta eously designed to meet the requirements t at I haveindicated.

In my claims I use the word carbon in its most general form, thereforeincluding graphite as well as other amorphous varieties. By domes I meancompartments of any desirable configuration so laced in and above thebath that they co lect and hold for delivery the products ofelectrolysis.

I claim:

1. In combination in an electrolytic cell for producing alkali metal anda halogen fromfused alkali metal halide, a compartment for the receptionof the material to be electrolyzed, a su merged compartment for thecollection and delivery of thehalogen,

and a compartment for the collection and delivery of alkali metal.

2. In combination in an'electrolytic cell memes parts, a shell forretaining the fused bath, an

anode, a cathode, impervious walls, a submerged dome and perviousdiaphragm bounding and constituting a submerged compartment forcollecting chlorine, a second compartment for collecting the alkalimetal produced, and a third compartment for rereiving the material to beelectrolyzed.

4. An electrolytic cell roducing alkali metal and a halogen from usedalkali metal halide, including as principal component parts, a shell forretaining the fused bath, an anode, a cathode, impervious walls, a.submerged dome and ervious diaphragm bounding and constituting asubmerged compartment around and over the anode and extending upwardlyout of the bath for collecting the halogen, a second. compartment aroundand over the cathode and extending upwardly out of the bath forcollecting the alkali metal, and a third compartment distinct from theother compartments for receiving the material to be electrolyzed.

5. An electrolytic cell roducing alkali metal and a halogen from usedalkali metal halide including as principal component parts a shell ofiron with refractory lining for retaining the fused bath, an anode centrally located with reference to the cathode, a cathode externallylocated with reference to the anode, impervious walls, a submerged domeand pervious diaphragm bounding and constituting a. compartment aroundand over the anode and extending upwardly out of the bath for collectingthe halogen, a second submerged compartment around and over the cathodeand extending upwardly out of the bath for collecting the alkali metalproduced, and a third compartment distinct from the other com artmentswith relatively large exposure of ath surface for receiving the materialto be electrolyzed.

6. In a fused alkali metal halide electrolytic cell, the combination ofmeans for disengaging alkali metal and halogen, halogen collecting meansdisposed below the bath surface, metal collecting means, and means forseparately discharging the collected halo en and metal.

7. n a fused alkali metal halide electrolytic cell, the combination ofmeans for disengaging alkali metal and halogen, separate .lytic cell,the combination -collecting domes leading out halogen 'and metalcollecti means disposed below the bath surface, arid means fordischarging the collected halogen and metal.

8. In a fused alkali metal halide electro- 11. 1 1 if lumps 1ii enga'gina a i meta and a en, a en collectin g means disposed belh w the bithsurface, metal collecting means, means for separately discharging thecollected halogen and metal, and means external of said collecting meansfor replenishing the bath.

9. In a fused bath electrolytic cell, a submerged anode and a spacedsubmerged cathode, an interposed diaphragm, and separate of the bathabove said electrodes from opposite sides of said diaphragm.

10. In a fused bath electrolytic cell, a submerged anode and a spacedsubmerged cathode, one being annular and external of the other, aninterposed diaphragm, and separate collecting domes leadin out of thebath above said electrodes om opposite sides of said dia hragm.

11. In a fused ath electrolytic cell, a submerged central anode, anannular submerged cathode outside the anode, an interposed diaphragm, asubmerged dome above the diaphragm and the anode leading out of thecell, and a submerged dome above the diaphragm and the cathode leadingout of the bath.

12. In a fused bath electrolytic cell, a submerged central anode, anannular submerged cathode outside the anode and spaced from the cellwall, an interposed diaphragm, a submerged dome above the diaphragm andthe anode leading out of the cell, and a submerged dome above thediaphragm and the cathode leading out of the bath. I

13. In a fused bath electrolytic cell, a submerged central anode, anannular submerged cathode outside the anode, an interposed diahpragm, asubmerged dome above the diaphragm and the anode leading out of thecell, and 'a submerged dome above the, dia hragm and the cathode leadingout of the ath, said latter dome being spaced from the cell wall.

'14. In a fused bath electrolytic cell, a sub-- merged central anode, anannular submerged cathode outside the anode and spaced from the cellwall, an interposed diap ragm, a submerged dome above the diaphragm andthe anode leading out of the cell, and a submerged dome above the dia-'hragm and the cathode leading out of the ath, said latter dome beingspaced from the cell wall.

15. A. fused salt electrolytic cell comprising a reservoir compartmentnormally open to atmosphere, a metal collecting compartment having adischarge outlet leading out of the cell independently of the reservoircompartment an containing a cathode, and

a gas collecting compartment havin a dis charge outlet ading out of thecel independently of the reservoir compartment and containing an anode.

16. The method which consists in electrolyzing a fused alkali metalhalide salt, and

separately collectin the metal and the halogen below the bathdischarging same outside the cell.

17. The method which consists in electro-' side the cell, and feedingreplenishing salt into the open bath.

18. The method which consists in maintaining a fused alkali metal halidesalt bath having a lower electrolyzing portion and an upper reservoirortion, electrolyzing the lower portion, and separately collecting themetal and the halogen from the electrolyzing portion as released anddischargmg same outside the cell out of contact with the reservoirportion of the bath.

19. The method which consists in maintaining an open fused alkali metalhalide salt bath having a lower electrolyzing portion and an upperreservoir portion, electrolyzing the lower portion, separatelycollecting the metal and the halo en from the electrolyzing portion asre eased and, dischar same outside the cell out of contact wit thereservoir portion of the bath, and feeding raw material into the o nbath.

a 20. The process of producing alkali metal and a halogen consisting inthe electrolysis of fused halide in a cell wherein additional charges ofelectrol e are fed into a chamber which is separate by diaphragm andim-' level as released, and

collecting separately as released the products of electrolysis. 22. Theprocess which consists in an alkali metal halide, conducting the fu saltinto space which is out of contact with air electro yzing the fused salttherein, and collecting se arately and out of contact with air the netsof electrolysis.

'23. e, process which consists in fusing sodium chloride, conducting thefused salt into space which is out of contact with air,

electrolyzing the fused salt therein, and col-' lecting separately andout of contact with air the products of electrolys s. Signed at NiagaraFalls in the county Niagara and State of New York 28th day of July A. D.1922. JAMES cLoYn' DOWNS.

